Polarized Raman Spectroscopy of the Quantum Antiferromagnet FePS₃

Modern computing has evolved from vacuum tubes to solid-state transistors in silicon-based integrated circuits, with each step providing an exponential increase in computational power. A key limitation to a scalable computing architecture is identifying solid-state materials that reliably function as qubits. Candidate materials include SrTiO₃, ErFeO₃, and FePS₃. We investigate FePS₃, a van der Waals–bonded Mott insulator, known to be a quasi-2D Ising antiferromagnet. Using Raman spectroscopy, we probe inelastic light scattering from both lattice vibrations (phonons) and magnetic spin-wave excitations (magnons), as a function of temperature, magnetic field, and polarization, providing an accurate measure of its structural and magnetic properties. Polarization resolved measurements on FePS₃, as well as reference studies on MoS₂ and Si, highlight symmetry dependent scattering and clarify how selection rules govern observed Raman modes. Experimental measurements together with modeling of angle-resolved Raman spectra at various numerical apertures further reveal how polarization and optical instrumentation influences Raman intensities. These results provide insight into the vibrational and spin dynamics of FePS₃ and its potential relevance for scalable quantum computing.